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From: dale@lamont.UUCP (dale chayes)
Newsgroups: comp.dcom.telecom
Subject: Subscriber Line Interfaces (SLIC) characteristics ?
Message-ID: <159@vema.lamont.LDGO.Columbia.edu>
Date: Sat, 17-Oct-87 17:04:54 EDT
Article-I.D.: vema.159
Posted: Sat Oct 17 17:04:54 1987
Date-Received: Tue, 20-Oct-87 01:08:30 EDT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: Lamont-Doherty Geological Observatory N.Y.
Lines: 25
Keywords: telephone interface help
Approved: telecom@xx.lcs.mit.edu


I am (reluctantly) doing an interface between a PBX (probably a Mitel SX-20)
and a Magnavox MX-211 INMARSAT (ship earth station) and am in need of a (the)
reference that defines (electrikly) a Subscriber Line (SLIC?.)  

The MX-211 uses a '4 wire' phone line. I already have a '4-wire to 2-wire'
conversion that works, and the interface to get the MX-211 to establish 
a connection through a satellite. What I have yet to resolve is the 'off hook'
detector. The interface was built for a Hayes 1200 baud modem and the 'off hook'
is done with the other set of relay contacts that only appear to exist in
the Hayes 1200s.

It seems to me that the 'thing to do' is to supply a current source (as if
there was a 'local office' in my 4 to 2 conversion box, and detect 'off hook'
by from the current flow.

Comments, reccomendations, and a reference are welcome.

	Dale Chayes
snail:	Lamont-Doherty Geological Observatory, Palisades, N.Y. 10964
phone:	(914) 359-2900 ext 434 
net:	...!philabs!lamont!dale
fax:	(914) 359-6817
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